How many inches across is a 700c wheel?
03-16-07, 10:20 AM
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How many inches across is a 700c wheel?
I was under the impression that it was 28". But in another thread (https://www.bikeforums.net/showthread...=pelotonracer), someone said that 27" tires were "too big" to put on a 700c wheel. I'm was like, WTF, no, they're too small... BTW, 650c is 26", right? RIGHT?!?!
Someone clear this up for me?
Someone clear this up for me?
03-16-07, 10:27 AM
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https://sheldonbrown.com/tire-sizing.html will clear it all up for you.
a 700c*39 tire is really 700mm = 27.56"
a 700c*23 tire is 668mm = 26.3"
just to start
a 700c*39 tire is really 700mm = 27.56"
a 700c*23 tire is 668mm = 26.3"
just to start
Last edited by vpiuva; 03-16-07 at 11:11 AM.
03-16-07, 10:49 AM
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Originally Posted by pelotonracer
I always thought 700c meant 700mm! What? so apparently, 700=622.
https://www.sheldonbrown.com/tire-sizing.html
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03-16-07, 11:01 AM
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Originally Posted by pelotonracer
I always thought 700c meant 700mm! What? so apparently, 700=622.
03-16-07, 11:09 AM
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bike tires are usually square, as in the width of the tire= height of tire or profile=100%........so you add double the width plus 622mm(which is the standard ERD of a 700c rim) to get the diameter of the wheel with tire mounted
ERD= estimated rim diameter
so for 23's that would be 46+622= 668mm = 26.3 inches
27" wheels have an ERD of 630mm usually
IIRC with mtb 26" wheels the 26" measurement is accurate with tires that are 1.75"
ERD= estimated rim diameter
so for 23's that would be 46+622= 668mm = 26.3 inches
27" wheels have an ERD of 630mm usually
IIRC with mtb 26" wheels the 26" measurement is accurate with tires that are 1.75"
03-16-07, 11:26 AM
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Originally Posted by pedex
bike tires are usually square, as in the width of the tire= height of tire or profile=100%........so you add double the width plus 622mm(which is the standard ERD of a 700c rim) to get the diameter of the wheel with tire mounted
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03-16-07, 12:08 PM
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Tires are sold to fit the "bead seat" diameter on the rims. The 27 inch tire that was the "standard" for road bikes in the 1970's fits on a rim with a "bead seat" diameter designed for that tire, and the 700c tires that are standard today fit on a rim with a "bead seat" diameter designed for them. Not interchangeable.
A different question is "how many inches across is a 700c wheel, when you include the height of the tire"? Some bike designers seem to forget that different widths of tires impact the height measurement.
As measured from the ground to the top of the tire, a 700c wheel using a tire that is 28mm wide will be slightly taller than a 700c wheel using a tire that is 21mm in width.
In 2007, we have many road bikes that were designed for ultra-narrow 700c tires. If the owner tries to use 28mm or 32mm wide tires, the clearance between the tire and fork will be next to nothing, so owners are limited to ultra-narrow tires.
A different question is "how many inches across is a 700c wheel, when you include the height of the tire"? Some bike designers seem to forget that different widths of tires impact the height measurement.
As measured from the ground to the top of the tire, a 700c wheel using a tire that is 28mm wide will be slightly taller than a 700c wheel using a tire that is 21mm in width.
In 2007, we have many road bikes that were designed for ultra-narrow 700c tires. If the owner tries to use 28mm or 32mm wide tires, the clearance between the tire and fork will be next to nothing, so owners are limited to ultra-narrow tires.
03-17-07, 08:58 AM
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Originally Posted by pedex
bike tires are usually square, as in the width of the tire= height of tire or profile=100%........so you add double the width plus 622mm(which is the standard ERD of a 700c rim) to get the diameter of the wheel with tire mounted
ERD= estimated rim diameter
so for 23's that would be 46+622= 668mm = 26.3 inches
27" wheels have an ERD of 630mm usually
IIRC with mtb 26" wheels the 26" measurement is accurate with tires that are 1.75"
ERD= estimated rim diameter
so for 23's that would be 46+622= 668mm = 26.3 inches
27" wheels have an ERD of 630mm usually
IIRC with mtb 26" wheels the 26" measurement is accurate with tires that are 1.75"
ERD = EFFECTIVE RIM DIAMETER or spoke nipple seat to spoke nipple seat measured across (diameter) the rim to calculate spoke length.
